title: Coordination chemistry at carbon.
abstract: Electron-rich allenes and heterocumulenes are commonly described by the regular notations of organic chemistry. Following on from published results and recent computational studies, we present here a host of crystallographic and reactivity data, as well as theoretical results, that indicate a highly non-canonical bonding situation in many members of this series. These must actually be interpreted as coordination compounds, in which carbon serves as a 'central atom' that interacts with its 'ligand sphere' via donor-acceptor bonds, even if these internal ligands themselves are carbon based. This captodative description is not limited to compounds that supposedly comprise a carbon(0) centre, a peculiar oxidation state that can be probed experimentally by geminal diauration. As the available data suggest that this unconventional interpretation of C-C and C-X bonds is more generally applicable than previously anticipated, it may well affect our understanding of organic chemistry in general.
authors.affiliation: Max-Planck-Institut für Kohlenforschung, D-45470 Mülheim/Ruhr, Germany.
authors.forename: Manuel
authors.initials: M
authors.lastname: Alcarazo
authors.forename: Christian W
authors.initials: CW
authors.lastname: Lehmann
authors.forename: Anakuthil
authors.initials: A
authors.lastname: Anoop
authors.forename: Walter
authors.initials: W
authors.lastname: Thiel
authors.forename: Alois
authors.initials: A
authors.lastname: Fürstner
mesh_terms: D002244:Carbon / Q000737:chemistry*; D004583:Electrons; D008024:Ligands; D008697:Methane / Q000031:analogs & derivatives / Q000737:chemistry; D015394:Molecular Structure; D009570:Nitriles / Q000737:chemistry; D009930:Organic Chemicals / Q000737:chemistry*; D010084:Oxidation-Reduction; D010100:Oxygen / Q000737:chemistry; D010753:Phosphoranes / Q000737:chemistry
chemical_list: D008024:Ligands; D009570:Nitriles; D009930:Organic Chemicals; D010753:Phosphoranes; C030011:carbene; D002244:Carbon; D008697:Methane; D010100:Oxygen